Real time for what?

Posted Nov 15, 2012 11:34 UTC (Thu) by epa (subscriber, #39769)
In reply to: Real time for what? by gregkh
Parent article: LCE: Realtime, present and future

Hmm, you're right. I would draw a distinction between the software running on the air traffic controller's desktop (which has often been Unix for decades now) and the microcontroller which controls the air intake to the engines. The former has fairly relaxed real-time requirements (the display has to update, but once a second might be acceptable) and I would call it 'soft safety-critical'. The software running on your doctor's desktop PC could kill you if it displays the wrong notes and causes the doctor to prescribe the wrong medicine - yet this is not normally an application considered safety-critical where special software methods must be used to guarantee correctness. By contrast, a failure of the jet engine microcontroller (assuming it has one, I am speculating) can cause instant disaster.

Real time for what?

Posted Nov 16, 2012 18:29 UTC (Fri) by jtc (guest, #6246) [Link] (4 responses)

" The software running on your doctor's desktop PC could kill you if it displays the wrong notes and causes the doctor to prescribe the wrong medicine - yet this is not normally an application considered safety-critical where special software methods must be used to guarantee correctness."

It's also requires neither a soft nor hard real-time kernel. :-)

[On a complete tangent: Is anyone else getting completely sick of that constantly changing Perforce ad. that adorns the top and upper right side of almost every page on LWN. I find it quite distracting and have to move another window to cover the right side of the page each time I open a new lwn page, so that I don't have the ad. screaming at me all the time while I'm reading! They've been running this ad. for many weeks - it's about time the found a new sponsor. Argghh!]

Real time for what?

Posted Nov 16, 2012 18:40 UTC (Fri) by dlang (guest, #313) [Link] (3 responses)

I believe that as a subscriber you can disable advertisements.

LWN doesn't go after individual sponsors, they subscribe to an advertisement service that puts the ads in place based on their own criteria.

Real time for what?

Posted Nov 16, 2012 19:12 UTC (Fri) by Trelane (subscriber, #56877) [Link] (2 responses)

> I believe that as a subscriber you can disable advertisements.

At the Professional Hacker level or above:
https://lwn.net/op/FAQ.lwn#subs

Real time for what?

Posted Nov 16, 2012 21:06 UTC (Fri) by jtc (guest, #6246) [Link] (1 responses)

"At the Professional Hacker level or above:"

Damn. I'm a "starving hacker". I'll have to upgrade once I find a job.

Thanks for the info.

Real time for what?

Posted Nov 16, 2012 21:07 UTC (Fri) by Trelane (subscriber, #56877) [Link]

NP. Glad you found it informative. :)